Bakker, Inga (2025) Limited Surgical Benefit of Neoadjuvant Endocrine Therapy in Invasive Lobular Carcinoma: Dutch nationwide study. thesis, Medicine.
Full text available on request.Abstract
Introduction: Invasive lobular carcinoma (ILC) frequently presents with advanced locoregional disease. While neoadjuvant endocrine therapy (NET) represents one treatment option for hormone receptor-positive ILC, its surgical effect remains unclear. This study investigates the surgical outcomes in patients with lobular carcinoma treated with and without NET and hypothesizes that NET does not effectively downstage tumors or enhance cosmetic outcomes. Methods: Nationwide data from the Netherlands Cancer Registration of all patients diagnosed with ILC between 2011 and 2021 were analysed. Primary outcomes were type of surgery, rates of tumor-involved resection margins after breast-conserving therapy and proportion of patients requiring secondary surgery. Secondary outcomes included pathological response. Results: Among 14.974 ILC patients identified, 810 (5.4%) received NET. Positive surgical margins occurred significantly more frequently in the NET group compared to the non-NET cohort (37.6% vs 18.2%; OR: 2.34, 95% CI 1.84-3.00). The NET group demonstrated higher re-operation rates (14.2% vs. 5.5%). Ultimately, no difference was found in definitive type of surgery, in both cohorts many patients underwent mastectomy (50.5% vs. 48.9%). A pathologic complete response in the breast was observed in 2.2% of cases (18/810), and, from all cN+ patients, a pathologic complete response in the axilla was achieved in 9.6% of patients (16/169). Conclusion: In ILC, NET is associated with higher rates of positive margins and re-operations without an increase in breast-conserving procedures. These findings indicate that NET should not be used as the sole rationale for pursuing improved cosmetic outcomes in patients with ILC. Achieving optimal oncological and cosmetic outcomes remains challenging for surgeons. Further prospective studies are needed to better guide the use of NET, including its impact on resection volume and cosmetic results.
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Volders, José and Schuttevaer, Henriette |
| Faculty: | Medical Sciences |
| Date Deposited: | 14 Jan 2026 14:55 |
| Last Modified: | 14 Jan 2026 14:55 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3877 |
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